The Northeast Weather Blog...

Summer 2009 in review...

Posted by: Zachary Labe, 4:48 PM GMT on August 30, 2009

Summer Outlook (2009)...

(One of my pictures from the Hershey Gardens, Summer 2008)

First Thoughts...
Ah, the words of the Beatles best describe our current emotions...

Here comes the sun, here comes the sun,
and I say it's all right

Little darling, it's been a long cold lonely winter
Little darling, it feels like years since it's been here
Here comes the sun, here comes the sun
and I say it's all right

Little darling, the smiles returning to the faces
Little darling, it seems like years since it's been here
Here comes the sun, here comes the sun
and I say it's all right

Sun, sun, sun, here it comes...
Sun, sun, sun, here it comes...
Sun, sun, sun, here it comes...
Sun, sun, sun, here it comes...
Sun, sun, sun, here it comes...

Little darling, I feel that ice is slowly melting
Little darling, it seems like years since it's been clear
Here comes the sun, here comes the sun,
and I say it's all right
It's all right

And so it is here, the season of warmth, sunshine, happiness, clear sailing, gardening, and so much more; SUMMER. Last summer was characterized as a cool summer with a very abnormally cool August which included less than a handful of thunderstorm days for the entire month. And yet again here we are in Spring 2009 with the same old, same old, clouds and below normal temperatures. Whether one wants to blame one particular feature such as low sunspot counts or instead go with the flow of the ever-changing weather cycle, one cannot ignore the below normal temperatures we have had for nearly the past 365 days. Even with the absence of convective activity, we did manage a severe weather outbreak with a tornado in Lancaster County. So in this blog will feature all of your important questions answered...hopefully, hahaha. My thesis for this summer appears to be a relatively normal summer temperature wise with normal to below normal precipitation, nothing too extraordinary.

Revisiting typical summer time weather threats...
Well just a quick review on some of the dangers of weather that people face in the summer. The three main ones are heat, severe weather, and hurricanes. Now here in Pennsylvania we really do not see any direct hits from hurricanes, just the remnants. But severe weather and heat waves can be big threats here in Pennsylvania. First about heat... When high temperatures combined with high humidity dangerous heat indexes can be reached. In the winter it is wind chill and in the summer it is heat index. The heat index is not the actual temperature but it what an animal and human feel on the skin. When the heat index reaches certain standards then advisories may be posted. Below are the thresholds for the advisories.

(Courtesy of NOAA)
Below are the official definitions from NOAA of common advisories found when severe weather strikes in the summer time...
-SEVERE THUNDERSTORM or TORNADO WATCH Severe thunderstorms with large hail, damaging winds, and/or tornadoes are possible, but the exact time and location of storm development is still uncertain. A watch means be prepared for storms.
-SEVERE THUNDERSTORM WARNING A severe thunderstorm is imminent or occurring; it is either detected by weather radar or reported by storm spotters. A severe thunderstorm is one that produces winds 58 mph or stronger and/or hail 3/4 inch in diameter or larger. A warning means to take shelter.
-TORNADO WARNING A tornado is imminent or occurring; it is either detected by weather radar or reported by storm spotters. A warning means to take shelter.
-FLOOD WATCH Conditions are favorable for flash flooding. A watch means to get prepared for possible flooding.
-FLASH FLOOD WARNING Life-threatening flooding is imminent or occurring; it is either detected by weather radar, indicated by stream gauges, or reported by storm spotters. A flash flood is a flood that occurs very quickly; it is caused by heavy rainfall over a short period of time or from a dam break. A warning means to leave low-lying or flood prone areas.

Discussion for outlook...
As mentioned earlier this is a lack of a key player this summer as for making temperature and precipitation trends. We are coming off of what was a very intense, and somewhat unexpected second year in a row strong La Nina. La Nina 3.4 SSTs dropped down to an anomaly of -1degrees. After that January with the height we hit a bit of warmer surrounding the cool SSTs, but the Hadley cell transitioned us a bit towards cooler anomalies in March. But recently dramatic warming is evident in the equatorial central Pacific.

Fig. 1.1- Courtesy of NOAA; This shows the anomalies for the Nina 3.4 region. Note the evident warming and nearly cancellation of the cooler SSTs

But the affects on North America are not as quick to transition as they are on water temperatures. We still will see through the rest of the Spring a generally La Nina type Spring setup which favors cooler conditions in the east with averages near (-1)-(-3) For example current average for April for Harrisburg International Airport is a bit below -1. Looking at current computer model forecasts it appears we are transitioning into a weak El Nino status. Now we can't say the accuracy of these computer generated forecasts have been accurate especially after the failure this Winter for the La Nina, but they have been pretty steady in their prediction for Nino.

Fig. 2.1- Courtesy of NOAA; This shows the CFS model and ensemble forecasts for the ENSO status for the coming months.

My general thoughts are that we will have a pretty active jet stream with a deep trough across the West Coast. This will put the Pacific Northwest in a pretty wet pattern with storms transitioning into the Midwest. A heat ridge will form there with very warm temperatures at times and potential very large severe weather outbreaks courtesy of the clashing air masses. Then a trough will be located over the Canadian Maritimes slightly touching northern and central New England. I will say that it is interesting to note the CFS climate forecast model does predict a bit towards the opposite of my prediction instead putting a ridge in the west with a trough in the Midwest and a ridge in the east. There just has been this constant negative PDO and that just continues to favor troughing over the west as has been the pattern for quite a while. Also something of note is the well below normal sea surface temperatures off the East Coast as they are quite unusually cold for this time of year. This may help inhibit tropical impacts on the east coast once again preventing widespread rainfall. Looking at soil moisture at groundwater, they are below normal for much of the Middle Atlantic. This tends to have an impact on short term and even long term temperatures by the dry ground allowing the atmosphere to be dry and hot with limited cloud cover development thanks to a weakening of the condensation in the water cycle. While currently with the recent rain, the ground is moist, but it is being quickly taken in by the growing vegetation and it is not really helping any water table levels. As far as drought is concerned this summer, I was jumping on the bandwagon in the past weeks, but I am leaning away from something significant. The location most likely to receive the driest conditions will be in the southern border counties of York, Adams, Lancaster, Chester and also the far eastern counties of Northampton and Lehigh Counties. So an interesting forecast is in store this summer and quite a difficult one at that. I think my point of error leans toward my precipitation, but overall I remain confident. This summer lacks anything pointing in anything extreme for heat and or precipitation. Again it looks pretty typical although tropical activity should be quite lacking.

My forecasts for 2009 Summer...
Temperature- Temperature forecasts are pretty dramatically different from last year. It does not appear that cooler air temperatures are likely this year for most any locales at least here in Pennsylvania. We are on the verge of entering a weak El Nino status likely by late Summer. This will generally produce neutral conditions along the equatorial Pacific for most of the summer. But we are coming off a moderate to some would consider a strong La Nina status back in the winter season. This will leave residual effects of the La Nina, but not too the point of last years dramatic effects. Typically Nina status produces cooler anomalies for much of the Northeast. But with weakening effects and a jet stream of a strong ridge in the Midwest and a weak trough in the New England region, this will leave the cooler air to our north. A Bermuda high looks also likely to form pumping up the heat in the Middle Atlantic especially middle to late Summer. So for temperatures... (These are average anomalies statewide for each month of the summer; JJA)

June- (-.1)-(-.6)
July- (+.9)-(+.4)
August- (+1.1)-(+.6)

As you can see I am going with a gradual cooler June transitioning into a pretty warm August. But in reality those anomalies are not that intense either way. This will prove that the summer generally will be met with typical temperatures, that is heat waves, and cooler spells. We have been in a cool pattern for quite a while and I think that will continue through May and the first 3/4s of June, but we will finally transition out of this constant troughing pattern in the Northeast. Still though I do think New England especially middle to northern areas will see cooler than normal summer temperatures. I think the hottest weather will be located across the middle of the nation and the coolest temperatures over the Pacific Northwest thanks to the negative PDOs continued effects.

Precipitation- Mainly locations are starting the 2009 year off in a deficit in the rainfall department. While many people would not consider us to be in a drought especially after all of the rainfall recently, most of the state has rainfall anomalies at (-3)-(-6)inches. For example Harrisburg International Airport has a 5.22inch deficit for the year and Williamsport Climate Reporting Station has a 3.19inch deficit. Locations in the western part of the state are running a bit better in the rainfall department, but still below normal. Pittsburgh has currently a 1.97inch deficit. Now while we have entered a relatively rainy pattern, it still really has not put a dent in the deficits and once the typical stratiform rainstorms end by late May and our rainfall becomes convective, it will become more unreliable for daily or weekly rain. I expect this summer to be characterized by several day or week periods of little to no rain followed by a deluge of heavy thunderstorm rainfall. Looking at the jet stream track the ridge of heat looks to be centered in the middle of the nation with the jet stream weak trough over New England. This puts our area at risk for large complexes of thunderstorms, but they would favor northern parts of the state and southern portions would be left in the dust. With cool Sea Surface Temperatures off the Atlantic and high shear levels along with blocking highs, it seems unlikely for much tropical activity. Any remnants of tropical systems would likely be from Gulf of Mexico storms which have a higher probability to track elsewhere other than the Northeast. So for my forecast rainfall looks to be near normal for western and northern areas thanks to being closer to the active jet. Southern areas should be below normal by 1-3inches for the entire summer. They will be affected by a consistent downsloping.

Severe Weather- This forecast is just experimental, but anyways it does appear possible for some large severe weather outbreaks especially favoring the month of July and early August in the heart of summer. As mentioned earlier large complexes of thunderstorms, MCS, are very possible with the highest threat probability for northern portions of the state. Intense positive CTG lightning strikes and damaging winds are always possible from these systems. As far as sever weather compares to other seasons, I do not see anything too unusual as far as being widespread. Reports will probably be a bit more than the summer of 2008, but far less than the near record breaking June of 2007 and the entire summer of 2007.

Final Thoughts...
This forecast did cause me a few problems coming up with especially with all of the opposite attracting factors. Unlike this previous Winter and Summer, there are no clear cut factors to pinpoint one extreme to the next. But looking at the overall current status of the pattern, it is clear that the Summer should feature heat waves and cooler patterns. Dry spells may be common especially as it appears that a predominant blocking high over the Southeast should keep most tropical activity away from the East Coast, that should be good news to many though. My main area for tropical concern this year is the Gulf of Mexico and southern Texas coast. The East Coast appears to luck out at least with the pattern as many tropical systems will feature turning out-to-sea fish storms. But it only takes on rogue storm like Andrew in 1992 to dominate a season. The saving grace to potential drought is the active northern jet stream which may feature some decent thunderstorm complexes on occasion especially in months such as July. With the season already starting out in a deep deficit for most locales, I find it difficult that we would be coming up on the positive side of anomalies by the end of August. Keep in mind this summer outlook is for the meteorological summer months of June, July, and August. At the end of August, I will issue my recap blog taking a look at my verification of accuracy for my forecast. So far my Summer 2008 outlook and Winter 2008-2009 outlook have fared excellent with only a few minor precipitation errors in some regions of the state so hopefully this outlook pans out too, although I will admit confidence level is a bit below status quo. Looking ahead, my annual Earth Day blog will be posted this coming Tuesday on April 22. It will feature environmental tips and some conclusions we can make about climate change. The blog will not be a debaticle on global warming, but it will instead take the approach of conserving the environment as it can only better our future. I hope everyone has a wonderful and safe Summer!!!

Summer 2008 Outlook... Link.

"Here north of Harrisburg 2009 statistics"
(Severe Weather Stats...)
Severe Thunderstorm Watches- 1
Severe Thunderstorm Warnings- 0
Tornado Watches- 0
Tornado Warnings- 0
Total Thunderstorms- 3

(Precipitation Stats...)
Flood Watches- 0
Flood Warnings- 0
Monthly Precipitation- 2.27inches
Yearly Precipitation- 5.52inches

(Temperature Stats...)
Heat Advisories- 0
Excessive Heat Warnings- 0
90degree days- 0

Categories: Summer Forecast

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101. Zachary Labe 7:06 PM GMT on September 04, 2009
weathergeek5- Looking beautiful for the next seven days. A back door cold front may try to move in early next week with clouds, but that is uncertain. lawntonlookers- Station is PA-DP-15. No problems on my end for the blogs, so not sure. Member Since: December 14, 2007 Posts: 253 Comments: 14312

102. originalLT 7:16 PM GMT on September 04, 2009
Hi Blizz and everyone, that new invest looks solid already. Member Since: January 31, 2009 Posts: 0 Comments: 5058

103. lawntonlookers 7:48 PM GMT on September 04, 2009
Thanks Bliz. Mine is working okay today after I ran a spy check. I will keep a watch on you rain fall reports. Looks like a nice rain guage from what I was reading on the slide presentation. I hope it is strong enough the prevent breakage when the water freezes. I don't know how many gauges I have had over the years the get rain water in them and then before I can empty it it cracks. Out for the day. May check back in the morning but if not have a great Labor Day weekend. Member Since: March 22, 2006 Posts: 9 Comments: 1570

104. upweatherdog 7:56 PM GMT on September 04, 2009
Afternoon Blizzard! I might be going brown trout and salmon fishing later at the mouth of a river on Lake Superior. We probably will be going around 8:00pm, when the sun sets and around when the moon rises. Have any idea of how a full moon affects salmon? Member Since: October 14, 2007 Posts: 173 Comments: 1365

105. Zachary Labe 7:57 PM GMT on September 04, 2009
upweatherdog- No, sorry I am not sure. I was out fishing for salmon on Lake Ontario near Oswego last August, but I do not know any fishing techniques. I went with a charter. *Just a reminder only a short time till my winter outlook debut. Sunday early morning it will be posted!!! Member Since: December 14, 2007 Posts: 253 Comments:** 14312

106. upweatherdog 8:00 PM GMT on September 04, 2009
I'll probably issue my winter outlook when Fall officaly starts. I don't even want to think about Winter now.lol Member Since: October 14, 2007 Posts: 173 Comments: 1365

107. Zachary Labe 10:55 PM GMT on September 04, 2009
upweatherdog- Well it is coming for you pretty soon up in there in northern Michigan. Member Since: December 14, 2007 Posts: 253 Comments: 14312

108. Zachary Labe 1:56 PM GMT on September 05, 2009
Another beautiful day! Member Since: December 14, 2007 Posts: 253 Comments: 14312

109. originalLT 4:46 PM GMT on September 05, 2009
Beautiful day here in SW CT. also, too bad for me I am working now indoors (snuk onto the computer for a few mins.) Old Erika now just seems like she won't go away, got to watch those remnants. 95L looks pretty well put together but looks too far N for much concern. Enjoy the holiday weekend! Member Since: January 31, 2009 Posts: 0 Comments: 5058

110. wxgeek723 6:12 PM GMT on September 05, 2009
Hey Blizz. Gorgeous day around here, though it's somewhat hot, not that the thousands of Labor Day travelers are complaining. All the highways around here are ridiculously clogged, even the back routes which I mentioned a couple of weeks ago which Pennsylvanians are discovering. Anyway, we all eagerly await your winter outlook and what you think we will see winter weather wise as a new decade commences. And what do you think may characterize our Fall weather? Member Since: August 28, 2008 Posts: 79 Comments: 2350

111. Zachary Labe 7:11 PM GMT on September 05, 2009
originalLT- Yep tropics have quieted down for now. There is just so much shear and dry air around the Atlantic coupled with a severe drought ongoing in the Caribbean. wxgeek723- Yep Labor Day marks another unofficial end of Summer. Lol, yep the most important blog of the year will be posted by 545am tomorrow morning. Member Since: December 14, 2007 Posts: 253 Comments: 14312

112. ronni9 3:27 AM GMT on September 06, 2009
want to wish all the WU friends a happy holiday weekend. R9 Member Since: December 3, 2007 Posts: 5 Comments: 848

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Cornell University- Atmospheric Sciences Student; Central PA SKYWARN Storm Spotter; American Meteorological Society Member; PA CoCoRaHS Branch Member

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